Studies on the Free Amino Acid Fraction of Soils

Physicochemical Fate of Sulfate in Soils

“…Early work showed the presence in soils of organic S compounds such as trithiobenzaldehyde, 9 and free cystine. 10 Other reports 11 -12 show that cystine and methionine are present in small amounts in soil hydrolyzates, and the reports indicate that they may occur as constituents of polypeptides in soils.…”

Glucose-induced nitrate assimilation in prairie and cultivated soils

“…Nitrate concentrations in three prairie and cultivated soils untreated or treated with glucose and KNO, and incubated at 30 'C for 0, 1, and 4 days. of soils with glucose and NO; results in a release of certain free amino acids (Putnam & Schmidt 1958;Paul & Schmidt 1961). If the addition of glucose and KNO, to soils induced peptidase activity that, in turn, caused a release of amino acids, then the increase in free amino acids or their deamination production (NH:) would inhibit ANR (Rice & Tiedje 1989;McCarty & Bremner 1992).…”

Growth-Modifying & Antimetabolite Effects of Amino Acids on Chrysanthemum

“…The question of the significance of free amino acids in soil or other cultural media has received attention in recent years in the fields of plant physiology (1,3,7,13,14,15,16,17), soil microbiology (4,5,11,16) and soil chemistry (9,10,12). Although it originally appeared that free amino acids were not to be found in soils, later reports (2, 10) indicated they could be extracted with aqueous and alcoholic solutions and determinations made with chromatographic methods.…”

“…Recently it was found that R. ineliloti and the nodules fronm several legumes and from alder contain one or more of the cobamide coenzyme(s) (10). The coenzyme in R. meliloti (11) has been isolated and identified as the 5,6-dimethylbenzimidazole derivative (vitamiin B1.2 coenzyme).…”